Convert an integer to its binary representation using a simple stack-based algorithm.

integer-to-binary.js

function integer_to_binary ( integer ) {
    if ( ( toString.call( integer ) !== '[object Number]' ) || ( integer < 0 ) ) {
        return null;
    } else if ( integer === 0 ) {
        return '0';
    } else {
        var stack = [];

        // var STACK_CAPACITY = 8;

        while ( integer > 0 ) {
            var bits = ( integer % 2 );

            if ( typeof STACK_CAPACITY !== 'undefined' && STACK_CAPACITY !== null ) {
                if ( ( toString.call( STACK_CAPACITY ) === '[object Number]' ) && ( STACK_CAPACITY > 0 ) ) {
                    if ( stack.length === STACK_CAPACITY ) {
                        throw new Error( 'Sorry. The bit stack cannot handle any more than ' + STACK_CAPACITY + ' element' + ( ( STACK_CAPACITY === 1 ) ? '' : 's' ) + '.' );
                    }
                }
            }

            stack.push( bits );

            integer = Math.floor( ( integer / 2 ) ); 
        }

        var binary_string = '';

        while ( stack.length > 0 ) {
            binary_string += stack.pop();
        }

        return binary_string;
    }
}